A boat propulsion engine (1) comprises a main body (4) that extends substantially vertically in relation to a hull (Si), a lift generator (20) disposed in a rear portion of the main body (4), and supporting bodies (24) that support the lift generator (20) on the main body (4). The lift generator (20) has a surface (21g, 21h) that extends transversely relative to the main body (4) and that is located behind at least the main body (4). The supporting bodies (24) extend backward from the main body (4) to the lift generator (20) in a single vertical direction relative to a surface (21g, 21h) of the lift generator (20).